Method of fabricating track laying vehicle shoes



March 23, 1948 c. a. SWEN'SON 2,438,424

METHOD OF FABRICATING TRACK LAYING VEHICLE SHOES Filed May 18, 1944 v Patented Mar. 23, 1948 METHOD OF FABRICATIN G TRACK LAYING VEHICLE SHOES Carl E. Swenson, Rockford, Ill., assignor, by mesne assignments, to the United States of America, as represented by the Secretary of the Navy Application May 18, 1944, Serial No. 536,102

3 Claims. 1

My invention relates to track shoes for track laying vehicles, such as military tanks and crawler-type tractors, and my invention relates also to a method for making such track shoes.

It is an object of my invention to provide an improved track shoe and an improved method of mak ng the same which are such that a minimum amount of metal and a minimum time are required for making the shoe whereby the shoe may be economically manufactured. It is another object of the invention to provide an improved shoe construction which is light but yet is strong.

The invention consists of the novel constructions, arrangements and devices and of the novel methods and processes to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will appear from the following description of a certain preferrd embodiment of track shoe and a certain preferred method for making such embodiment which are described with reference to the accompanying drawing, wherein:

Fig. 1 is a side elevation of a portion of a tank track embodying the principles of the invention;

Fig. 2 is a side elevation on an enlarged scale, partially in section, of a tank track shoe constituting a part of the track illustrated in Fig. 1 and embodying the principles of the invention;

Fig. '3 is a plan view of rolling mechanism for rolling out strips of metal used in making parts of the track shoe, as will be hereinafter described;

Fig. 4 is an exploded perspective view of the two halves of the track shoe;

Fig. 5 is an exploded perspective view of the shoe in an intermediate stage'of manufacture; and

Fig. 6 is a plan view illustrating a method of assembling a trunnion pin in the shoe.

Like characters of reference designate like parts in the several views.

As an example of one form which my invent on may take, there is illustrated in the drawing and particularly in Fig. 1 thereof, a track for military tanks or crawler-type tractors comprising a plurality of track shoes In which are pivotally connected together by means of connector links H. The track is adapted to travel around sprockets and guide pulleys (not shown) of a tank or tractor, in accordance with the well known use of such track, and each of the connector links H is provided with a guide portion I2 for holding the track against lateral displacement with respect to the sprockets and guide pulleys. Each shoe has a pair of trunnion or pintle pins l3 extending transversely therethrough, one at either end of the shoe, and these pins project beyond both sides of the shoe to form trunnions M which are secured in the respective ends of the connector links H. The pins l3 are mounted in cylindrical bores l5 (see Fig. 2) in the shoes I6 through the medium of sleeves it of soft rubber under compression, and the sleeves l6 permit the pins l3 a limited amount of movement within the bores in order to better allow the track to wind around the sprockets and guide pulleys (not shown) with which it cooperates. Each of theshoes Ill is provided with a cleat or grouser H which is welded to the shoe, and the grousers H on the track shoes function, as is apparent, to provide greater traction between the tracks and the ground or greater traction of the tracks with respect to the water if the tracks are used on an amphibian vehicle such as is, for example, shown in the co-pending application of Benjamin A. Swennes, Serial No. 508,304, filed October 30, 1943. Each shoe I0 is preferably provided with a central shoe lightening bore [8 therethrough, and a cap 19 is fixed in each end of the bore for sealing it.

At present it is the practice to construct a shoe of this general type in the form of an integral forging. Because of the great width of the shoe, it has not been possible to form the bores I 5 in the forging operation, even in rough form. The practice, therefore, is to form the bores by drilling entirely through the shoe from one side to the other. In doing so, about forty per cent of the metal content of each shoe is removed, and this boring operation has proved to be very difficult, laborious and t me consuming. Because of the great length of the bores, the likelihood of error in the drilling operation becomes progressively greater the deeper the bore becomes. The forged metal used in the'shoe is very toughin order to resist wear in operation, and this increases the difliculty of the boring operation. However, the most undesirable characteristic of this method of forming the shoes is the time consumed in the machining operation. In viewof the military use to which these shoes may be put and the demand for speed in producing the track, it is extremely important that the amount of time consumed in machining the shoes be reduced if possible.

The present invention eifects a very substantial saving in the processing time, which may amount to more than fifty per cent of the time required in the finishing of the forged shoes, and also effects a very substantial saving in material, which may run as high as forty per cent. In its latter aspect,: the. invention proposes to form the trunnion berets in such a manner that finishing of the trunnion bores is not necessary, so that the weight of the shoe in finished form is substantially the same as the weight of the shoe before finishing, whereas 'u'i'id'e'rthexpres'ent method, the rough blanks in the average shoe weigh about thirty-eight pounds as against twenty-four pounds in the finished shoe.

In accordance with the invention; the shoe is built up from two different pieces of material, namely, :an upper half and a lower half 2| each of which extends transversely of the track-shoe and is uniform in cross-section throughout its length, Each of the sections 20 and 2i is formed with a pair orseeeea parallels'emi-circular channels 22 and 23 and with a generally rectangular 'chailliel 2 between the marinas 22 "and 2s. The

shoe halves 20' and iii are identicalwith the exceptijo ri that the fialfifll i's preferably provided with ribs 25 ontlie front and rear ends of the shoe and the half 20 has a substantially flat outer face 26 while the outer fae 2'! or the half 21 need not be absolutely flat. THechanneIsZZ, 23 and 24 in each of the shdesee ieasare definedby wall persons 23, 29', at and 3|, andthe w ll portions of the two shoe seeeans'ar in ab littingv relationship li'ithe completed shoe so that the channels 22 '23 the trunnion bores l5 and the channels 2%, formthe central bore IS in the shoe.

Eaehof thehalves 20 and 2! may be formed by a rolling operationin a steel him. The rolling operation is illustrated in lfig. 3, therbillet of steel, indicated at 312, being passed between a pair of rollers 3 an d 34 to produce rolled metal strip35. The roll3 is providedwith appropriately shaped ridges36 and 31 thereonfor formingthechannels 22, and 24s; the rolled-strip 35. It will be apparent that the strip 3 5,- w' hich is uniform in cross-section after the rollingopera-tion, may also, if desired, beformed by extruding the metal through appropriately shaped dies (not shown).

After the rolling. operation has been completed, the rolled strip is severed as at 38 into the individual shoe halves 29 or 2|, asthe case may be. This is done by a sawing operation which may take place either while the rolledstrip is still in a hot and relatively soft stage orafter it has cooled. Prior to the asembly oi the shoe halves together, their walled portions 28, 29, 30 and 3! may be machined on their edges, if necessary; so that there may be a close abutting fit of the wall portions of the two halves together. The two halves are put in assembled relationship as shown in Fig: 5, and the halves are welded together at their edges, as at 39, toform a; unitary piece; It is obvious; of course, thatthe strips 20 and--21 could be welded togetherv prior to the severing operation, but itis preferredtoperform the welding operation after severing the strips into-shoe lengths. The pings F9 are then inserted into the central'bores It, ar'rd-the-plugs are welded about place. The two shoe halves are also preferably welded together within the central bore [8 between the plugs l9 and the sides of the shoe, as at 40.

In the completed shoe, the welding 39 functions to hold the shoe halves together at the front and rear ends of the shoe, and the plugs l9 and the welding 40 function to hold the shoe halves together in the central region of the shoe. The plugs I9 have the added function of excluding water or dirt from the interior of the central bore l3..

It is impracticable to io'irni a forged shoe having an opening corresponding to the opening l8 therein, with the thickness of the bridging walls 29 and 3Elseparating such space from the bores late mg reduced-to a minimum throughoutthe length thereof. In the present invention wherein this'space is formed by providing correspond ing:Cha.I 1n1S iI1;, theseparate halves of the shoe, the bridging walls may be made of uniformly minimum thickness and thereby the weight of the shoe may be brought to a minimum in proportion to-jts' strength. r

The trunnion pins I3 together with the sleeves l of ru b r Ieer Po it oned in the 1 9 1 wi u e of i edk m mb 4 N u nio pin l 3 with rings iii or -soft rubber bon ded thereto as es r ame're r d t rou t e 1 12 ne l-like member, Al into the respective trunnion bores i S The tunnel-like member 4| functions o o r ssib e est? W nq i a lv st rue s lt rs 1 o s ft bb mnd r hi so pressia en r di l lrwm imtsth ill fiignpins withihthebores l li while completely filling shown nd lsh r eptnnlv in ula a the cl ybe, p l mite a itwil besii a et to these Skilled the with. eh rl esmey made without departing from the principles of the invention.

1'; The method of fabricating a track laying vehicle' shoe having a pair of spaced parallel transve'rsely extending pintle bore's'therein, comprising the method steps of rolling ,masses of metal to formelongated strips each of which crosssection is uniform and corresponds to the side elevation of a half of the shoe divided on a plane bisecting the pint'le bores, and each of which has apair of spaced longitudinallyextending channels each corresponding to halfthe pintle bore. severing the rolled strips transversely to form complementary halves of the shoe, machining the matching edges of each shoe to form a close fitting edge, and securing the shoe halves together on those edges'to fornra finished shoe with the channels in the. shoe halvesextending transverseto form channels, smoothing the channel edges to form close abutting fit with a matching strip, securing the matching strips together on those edges, and severing said assembled strips transversely to form the shoes.

3. The method of fabricating a track laying vehicle shoe having a pair of spaced parallel pintle bores therein, comprising the method steps of forming metal strips which in cross-section are uniform throughout their lengths and correspond to side elevations of halves of the shoe divided along a plane bisecting the pintle bores, severing the strips transversely to form the shoe halves, smoothing the matching surfaces of each half to form close abutting surfaces, and Welding the halves together on those matching surfaces to form the track shoe.

CARL E. SWENSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

